Sensors that respond to light can be susceptible to exposure to laser radiation, such as laser threats (often referred to as countermeasures) and laser hazards (unintentional dangers). Research has sought to protect some sensors from these countermeasures. Such endeavors generally have one or more shortcomings, either in terms of sensor performance, cost, complexity, space required, etc.
It is known that certain gases can be used to attenuate specific laser lines with high efficiency. Previous attempts to protect a light sensor against laser countermeasures have involved filling a chamber within the sensor with an absorptive gas and attempting to permanently seal the chamber. Accordingly, the absorptive gas would constantly be in the light sensor's optical path. For a gas designed to protect against an in-band threat, this results in reduced in-band transmission and, therefore, constantly reduced sensor performance. In addition, the housing or chamber containing the gas within the light sensor needs to be well-sealed to prevent leakage over the lifetime of the sensor. This requires additional monitoring and constant maintenance efforts of a chamber.
What is needed is a low cost solution which lacks these shortcomings under normal operating conditions and which can be implemented when needed.